Probably better off bringing your own. I'm sure the resorts have them on the other islands. However, on the main island, if there are hire places - I didn't come across any. I'm staying at a beautiful black beach with a sensational crowded beach break, called Papara.
As for seafood, you can buy tuna, marlin and reef spiecies on the side of the road. Went to the main market in town, and saw absolutely no crab/prawns/lobsters - not sure what the story is there. Very few good restaurants around this island although I did find a good place near Teahupoo.
Seems like all the prosperity in Tahiti was created when the French Govt was Nuke testing. Since that stopped so did the local economy, many of the attractions are now either closed or in a state of disrepair - the aquarium, the Paul Gauguin museum, botanical gardens. People are really friendly, surf is amazing, and the island is stunning - I just get the sense that it's a bit unloved.
Heaps of white pointers..................... Euro topless sunbathers. Tahiti is one of the most beautiful places on earth, you just have to know where to go. You are right though, a lot of the hotels/resorts that had been there for years have gone. Its kinda sad but the outer islands are still sweet. Go discover.